As shown in FIG. 6, a traveling device 1 provided at a lower portion of a hydraulic shovel is configured such that: upper surface plates 4 of travel frames 3 for attaching crawler belts are integrally provided on both left and right sides of a center frame 2 positioned at a vehicle center; a travel motor attachment unit 5 is integrally provided on one end side of the travel frame 3; and the crawler belt (not shown) attached along the travel frame 3 is driven to rotate by a crawler belt driving unit (not shown) including a hydraulic travel motor attached to the travel motor attachment unit 5, a reducer, and a sprocket. A travel motor hydraulic pipe 6 is arranged from the center frame 2 to the hydraulic travel motor in the travel motor attachment unit 5 through an opening in an inner side surface of the travel frame 3.
In such a traveling device 1 at the lower portion of the hydraulic shovel, the travel motor hydraulic pipe 6, arranged from the center frame 2 to the travel frame 3, might be damaged by colliding with an obstacle such as a rock during an excavation operation.
In view of this problem, conventional configurations where a piping cover that covers the travel motor hydraulic pipe 6 to prevent the travel motor hydraulic pipe 6 from being damaged have been known (see, for example, Patent Documents 1 and 2).
Furthermore, there are following configurations (see, for example, Patent Documents 3 to 5), as hydraulic piping protecting means other than the piping cover. Specifically, a hose insertion space for the travel motor hydraulic pipe is continuously arranged from an inside of the center frame 2 to an inside of the travel frame 3, in the traveling device 1. The travel motor hydraulic pipe is disposed through the hose insertion space in the frame.    [Patent Document 1] Japanese Utility Model Application Laid-open No. S63-086168    [Patent Document 2] Japanese Patent Application Laid-open No. 2006-219871    [Patent Document 3] Japanese Patent Application Laid-open No. 2002-339402    [Patent Document 4] Japanese Patent Application Laid-open No. 2004-060210    [Patent Document 5] Japanese Patent Application Laid-open No. 2009-191555
However, the piping covers described in Patent Documents 1 and 2 might be damaged or deform by colliding with a large obstacle. This might lead to damage on the travel motor hydraulic pipe and a problem regarding a vehicle outer shape.
Specifically, Patent Document 1 discloses what is known as a widening type (variable gauge type) traveling device in which a gap between left and right travel frames can be widened and narrowed. In such a device, the travel motor hydraulic pipe is provided with extra length, so as to be adaptable to both the widened and the narrowed states. Thus, in the narrowed state, a space for bending the extra portion of the pipe is required. Thus, the piping cover needs to have a size large enough to accept the extra length of the bent pipes, and thus has larger chance of colliding with the obstacle. Therefore, the piping cover is likely to be damaged and deform, and the travel motor hydraulic pipe in the cover might also be damaged.
Patent Documents 3 to 5 disclose the configurations where the travel motor hydraulic pipe is disposed through the hose insertion space arranged from the inside of the center frame to the inside of the travel frame. The configurations can prevent the travel motor hydraulic pipe from being damaged, but have a problem that an operation for assembling the hydraulic pipe is difficult to perform. In an attempt to solve this problem, for example, further problems arise. Specifically, the configuration in Patent Document 5 requires structurally difficult changes such as forming hole a large enough to allow a hand to be put into the hose insertion space, and providing a pipe guide surface in the hose insertion space.